Quartz crystal oscillators (including quartz crystal resonators and quartz crystal oscillators), as basic components, mainly provide basic clock signals for digital circuit systems. They are composed of quartz crystal oscillators (i.e. resonators) with piezoelectric effects and extremely high quality factors, and oscillation circuits. They provide reference frequency signals in communication systems to keep frequencies synchronized between various communication devices; Provide clock signals in digital circuits to drive logical operations and achieve synchronous operations.